part of part of develops from develops from theca cell pre-theca cell externa theca cell 2024-09-30T11:10:15Z A specialized theca cell that forms the outer layer of the theca surrounding the ovarian follicle, appearing at the antral follicle. Originating from progenitor theca cells, theca externa cell is characterized by its fibroblast-like appearance and primarily function to provide structural support to the developing follicle. This cell produces collagen fibers and extracellular matrix components such as Col1a1 and Col1a2. structural theca cell theca externa